NAME
    Mail::SpamAssassin::Util::RegistrarBoundaries - domain delegation rules

METHODS
    ($hostname, $domain) = split_domain ($fqdn)
        Cut a fully-qualified hostname into the hostname part and the domain
        part, splitting at the DNS registry boundary.

        Examples:

            "www.foo.com" => ( "www", "foo.com" )
            "www.foo.co.uk" => ( "www", "foo.co.uk" )

    $domain = trim_domain($fqdn)
        Cut a fully-qualified hostname into the hostname part and the domain
        part, returning just the domain.

        Examples:

            "www.foo.com" => "foo.com" 
            "www.foo.co.uk" => "foo.co.uk"

    $ok = is_domain_valid($dom)
        Return 1 if the domain is valid, "undef" otherwise. A valid domain
        (a) does not contain whitespace, (b) contains at least one dot, and
        (c) uses a valid TLD or ccTLD.